Elements of life

Announcements Project proposals due in asap We have 1 quiz left on nonmetals and alloys which will be Tuesday next week Term 4 grades need to be finalised next week so ensure all assignments are handed in please.

Goal To understand the elements and compounds that make up our bodies. Question of the day: Why is there so much oxygen in our body? Previous answer: Carbon is added to iron to create steel, which is stronger and harder than pure iron. Previous question: Why is carbon added to iron?

Human body composition The human body is mostly made of different types of compounds by mass Water - 65% (H,O) Protein - 20% (H,C,N,O) Lipids - 12% (H, C, O) Nucleic acid 1.1 % (H,C,N,O, P) Other – 1.9% Talk about humans floating / sinking as mostly water Lipids are a group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E, and K), monoglycerides, diglycerides, triglycerides, phospholipids, and others. The main biological functions of lipids include storing energy, signaling, and acting as structural components of cell membranes.[4][5] Lipids have applications in the cosmetic and food industries as well as in nanotechnology.[6]

Elements of life Humans are mostly made up of four elements by atomic number Hydrogen 62 % Oxygen 24% Carbon 12% Nitrogen 1.1% The remaining 0.9% are made up of other elements

Human body composition The human body is made up of these elements by mass. Oxygen, carbon, hydrogen and nitrogen make up 96% of the mass.

Elements of Life Talk about how people need salt The body uses sodium to control blood pressure and blood volume. Your body also needs sodium for your muscles and nerves to work properly. Copper works with iron to help the body form red blood cells. It also helps keep the blood vessels, nerves, immune system, and bones healthy.

Carbon Carbon can make many bonds through electron sharing Carbon will bond with hydrogen, oxygen, and nitrogen These bonds make the “backbones” of proteins, lipids, and nucleic acid

Other elements The last 4 % are made of small amounts of many elements The alkali and alkaline earth metals form ions that help regulate the cells The nonmetals are used in small amounts for nucleic acids and proteins Nonmetals like phosphurus found in DNA. Sulfur is used in the amino acids cysteine and methionine.[2] Phosphorus is an essential element in the formation of phospholipids, a class of lipids that are a major component of all cell membranes, as they can form lipid bilayers, which keep ions, proteins, and other molecules where they are needed for cell function, and prevent them from diffusing into areas where they should not be. Phosphate groups are also an essential component of the backbone of nucleic acids and are required to form ATP – the main molecule used as energy powering the cell in all living creatures.[3]

Trace elements Many trace amounts of transition metals are used in some proteins The metals are chemically needed for the protein to work Example: hemoglobin Eat food Rich in iron after giving birth or periods. Iron-deficiency anemia, the most common form of anemia, is a decrease in the number of red blood cells caused by too little iron. Without sufficient iron, your body can't produce enough hemoglobin, a substance in red blood cells that makes it possible for them to carry oxygen to the body's tissues. As a result, you may feel weak, tired, and irritable. About 20% of women, 50% of pregnant women, and 3% of men do not have enough iron in their body. The solution, in many cases, is to consume more foods high in iron. Beef, liver, clams, spinich, brocolli.

Class Review If you were to only eat lipids or carbohydrates (H, C, O). Would we be healthy? Why? What else might we need? The human body has 0.00067% iron. Does this mean we don’t need iron? Why or why not? Although carbon is only 12% of the body, what makes carbon so important?

Vocabulary Protein: large complex naturally produced molecules made of amino acids Lipid: fats that don’t mix with water Nucleic acid: any long chain molecule that stores the information for the cell Trace: an extremely small amount of some chemical component hydrophobic

Further Reading http://en.wikipedia.org/wiki/Composition_of_the_human_body